A trio of mysterious gaping holes in northern Siberia has spawned many theories about the craters' origin, but scientists have suggested some concrete explanations.

In mid-July, reindeer herders stumbled across a crater that was approximately 260 feet (80 meters) wide, on the Yamal Peninsula, whose name means "end of the world," The Siberian Times reported. Since then, two new chasms - a 50-foot (15 m) crater in the Taz district and a 200- to 330-foot (60 to 100 m) crater in the Taymyr Peninsula - have also been reported.

Neither aliens nor meteorites caused the strange cavities, as some had speculated, but the true explanation could be exciting nonetheless. Russian scientists have launched an investigation to find out more.

"My personal opinion is it's some type of sinkhole," said Vladimir Romanovsky, a geophysicist who studies permafrost at the University of Alaska Fairbanks. Sinkholes are pits in the ground formed when water fails to drain away.

The water likely came from melting permafrost or ice, said Romanovsky, who has spoken with the Russian scientists investigating the site. But whereas most sinkholes suck collapsed material inside, "this one actually erupted outside," he told Live Science. "It's not even in the [scientific] literature. It's pretty new what we're dealing with," he added.

Early on, polar scientist Chris Fogwill of the University of New South Wales, in Australia, suggested the first hole was created by the collapse of a pingo, a large, earth-covered mound of ice that usually forms in Arctic and subarctic regions.

Kenji Yoshikawa, an environmental scientist also at the University of Alaska Fairbanks, said he also thinks that a drained, collapsed pingo pond is the most likely explanation for the Yamal Peninsula pit. In Alaska, similar pingos exist in the Northern Seward Peninsula and near the city of Nuiqsut.

But Romanovsky said the hole doesn't look like a typical collapsed pingo; such features usually form from larger mounds that slowly cave in over a period of decades, with all the material falling inside.

From the photo of the Yamal crater, "it's obvious that some material was ejected from the hole," Romanovsky said. His Russian colleagues who visited the site told him the dirt was piled more than 3 feet (1 m) high around the hole's edges.

The crater's formation probably began in a similar way to that of a sinkhole, where water (in this case, melted ice or permafrost) collects in an underground cavity, Romanovsky said. But instead of the roof of the cavity collapsing, something different occurred. Pressure built up, possibly from natural gas (methane), eventually spewing out a slurry of dirt as the ground sunk away. Anna Kurchatova, a scientist at the Sub-Arctic Scientific Research Center in Russia, made a similar observation to The Siberian Times.

The photo of the crater rim shows some vegetation that does not appear freshly grown, which suggests the hole may be several years old, Yoshikawa said. Romanovsky said it might be more recent, but investigators will need to look at archived high-resolution satellite images to pin down exactly when the crater appeared.

And many other questions remain: If a sinkhole erupted material, why is the hole's border so round and even? Would there be enough gas to fuel such an eruption, and where did such gas come from?

This part of Siberia contains deep gas fields, and it also contains a lot of small lakes, which formed between 4,000 and 10,000 years ago when the climate was warmer, Romanovsky said. Perhaps these odd holes developed in the same way that sinkholes did, but later expanded.

Domes of natural gas also exist in the United States, located east of the Sagavanirktok River in Alaska's North Slope Borough.

The development of permafrost sinkholes could be one indication of global warming, Romanovsky. "If so, we will probably see this happen more often now."

Comment:

"It's not even in the [scientific] literature..."

Wow, are we living in 'interesting times' or what?!

We can offer an alternative explanation to pingos and man-made global warming.

For an explosion you need two things: an igniter and combustible material. The Arctic, as with many other places on Earth is outgassing methane at never-before-seen rates. Lightning discharge events are also increasing in intensity and frequency because the solar wind is being grounded while comet dust loading of the atmosphere increases nucleation and resistance, leading to greater precipitation and greater charge-rebalancing respectively.

Reader Comments

Underground Bases and Tunnels - What is the government trying to hide? by Richard Sauder, Ph.D talks about large underground drilling machines that make symmetrical holes with smooth sides that definitely resemble the ones in these pictures and video. Tunnel Boring Machines or "TBM's" (made by Robbins Co.) and Vertical Shaft Drilling Machines are massive. The ones depicted are not 80M wide, but who knows. Food for thought.

I work in heavy construction as an engineer. I have drilled large diameter holes (even operated the heavy machinery on a job or two). I recall one job we were drilling 25-ft deep, 2.5-ft diameter holes and placing "quick lime" at the bottom. The lime reacts violently with water in the soil (which we intended for this project), and I recall some of those holes "blowing up" after the lime was placed. Then there are the more common drilled shafts which we used to fill with gravel in a controlled manner, compacting as we filled to improved foundations. As the gravel is dropped, there is some blow out as the air in the hole is displaced, and material is ejected. The reason I say so is not that this is what happened here, but to point out that either some reaction in the soil itself, or the collapse of the sinkhole roof (sinkholes are erosion features that start underground and propagate upward until the cavity is large enough and the roof thin enough that the soil can no longer "arch" across the cavity. When a sinkhole collapses, I don't think it's a stretch for the force of expelled air to blow some soil out. The volume of soil around the rim is only a small fraction of the actual void.

A maar is a shallow volcanic crater with steep sides that is surrounded by tephra deposits. The tephra deposits are thickest near the crater and decrease with distance from the crater.

A maar is formed by one or more underground explosions that occur when hot magma comes into contact with shallow ground water to produce a violent steam explosion. These explosions crush the overlying rocks and launch them into the air along with steam, water, ash and magmatic material. The materials usually travel straight up into the air and fall back to Earth to form the tephra deposits that surround the crater. If the tephra lithifies, it will become an igneous rock known as tuff.

Perhaps these were formed above the water table leading to a lack of the characteristic steam explosion.